1. Field of the Invention
This invention relates to an improved landscape edging product that provides improved resistance to movement after it is installed in the ground and that requires no greater installation effort than do prior art landscape edging products. This invention further relates to methods of manufacturing and using the landscape edging product. In particular, this invention provides an extruded and molded edging product that comprises, when installed, an underground anchoring panel and an integral above ground trim member. The anchoring panel comprises a plurality of soil sockets, which are concave depressions formed in one or both faces of the anchoring panel. The landscape edging structure of this invention provides increased resistance to pulling out of the soil once it is installed.
2. Discussion of Prior Art
In many instances it is desirable to separate different types of plants in a garden and to prevent undesired commingling of plants, in particular to separate a grass lawn area from an area desired to be used as a flower bed or other grassless landscaped area.
It has long been known that a distinct border could be formed between a lawn area and a garden area by implanting an elongated, perhaps flexible edging product along the path desired for the border. Previously known edging products typically comprise a root barrier that is buried vertically in the ground along the border and an integral above ground trim member continuously attached to the top of the root barrier. The root barrier prevents the growth of grass and other shallow roots across the border and also maintains the edging product in position. The trim member forms a visually distinct and preferably attractive border, inhibits the growth of grass and other vegetation across the border, and contains mulches, soils, water, and other materials on the side of the border on which they are placed.
The prior art contains numerous examples of extruded plastic edging materials, some of the known references including U.S. Pat. No. 4,281,473, issued to Emalfarb, et al. on Aug. 4, 1981 for a Landscaping Bed Divider, U.S. Pat. No. 4,321,769, issued to Tisbo, et al. on Mar. 30, 1982 for Edging Strip, U.S. Pat. No. 4,644,685, issued to Tisbo, et al. on Feb. 24, 1984 for Edging Strip, and U.S. Pat. No. 3,841,022, issued to Thodos on Oct. 15, 1974 for Lawn Edging Device.
These edging products are generally installed by excavating a trench of suitable width and depth at the location desired for the border, placing the edging product in position in the trench, with its root barrier portion in the trench below ground level, and closing the trench such that the trim member protrudes through the surface of the soil.
One difficulty encountered with previous edging products is a tendency for them to emerge from the ground over time, either from being pulled or struck by lawn mowers or other tools, or due to heaving of the soil due to freezing and thawing in winter. Reinstallation of edging segments that have emerged from the ground can be as difficult or more difficult than the original installation. It is therefore desirable to provide an edging product that is locked into the soil when it is installed and that provides increased resistance to movement relative to the soil.
Several prior patented devices address anchoring edging products into the ground. See, e.g., U.S. Pat. No. 4,321,769 (1982) which discloses horizontally extending ribs molded integral with the root barrier; U.S. Pat. No. 4,281,473 (1981) which discloses upwardly and outwardly diverging lips formed near the bottom of the vertical root barrier; and U.S. Pat. No. 4,644,685 (1987) which discloses a plurality of ears hingedly formed by cutting flaps in the root barrier, each ear extending away from the root barrier to anchor the edging strip.
In practice, the known prior art edging designs do not adequately anchor the edging into the ground because they do not provide sufficient generally non-vertical surface area in contact with the soil to prevent vertical movement of the edging relative to the soil. Horizontal ribs affixed to the edging which would be large enough to provide the desired horizontal surface area are undesirable because they require a larger trench to be excavated for installation, and because they interfere with the lateral flexibility of the edging and interfere with its use for short radius curves without cutting the ribs. The solution of U.S. Pat. No. 4,644,685, which discloses hinged "ears" extending upward and outward from the root barrier, is undesirable because it does not provide much non-vertical surface area, and because it provides holes in the vertical edging member where the hinged ears are affixed, through which undesirable roots, materials and insects can migrate.
The above discussion demonstrates the need for an improved edging product that will provide increased resistance to emergence from the soil while requiring no additional effort to install. It is further desired that the vertical anchoring panel of the edging be impermeable to plant roots and insects, that it be rigid enough to stand up to the rigors of installation and use, but that it be sufficiently flexible to allow construction of short radius curves in the border it is used to form, and that it have a large non-vertical surface area in contact with the soil to resist vertical movement of the edging with respect to the soil.